In the case of the conventional variable resistance, a slide member connected to a terminal moves slidingly over the resistance between adjacent terminals connected to the circuit so as to set a resistance value proportional to the distance between terminals. When the slide member moves slidingly directly over the resistance body, the characteristics of the resistance body covered with metal varies due to the wear and the friction in such a manner that the set resistance value often deviates. Further, there exists the semi-fixed variable resistance which is an improvement of the above mentioned variable resistance, which is so designed that the electrode parts are led out of the resistance body, whereby there is a difficulty that when the semi-fixed variable resistance is arranged in the circuit and set for adjusting the resistance value, the slide member often drops on the insulation part between the electrodes in such a manner that the slide member is insulated from the electrodes. Hereby, even if the slide member is set on the electrode, it often moves and drops on the insulation part due to the vibration, the shocks and so on.